How did the common view of Abelard as a critical rather than a constructive thinker emerge?

The first place to look is at the manuscripts (surviving or known from references in catalogues and elsewhere) of his works. Thanks to the Checklist, it is possible to find out at a glance which works by or about Abelard were widely copied in the Middle Ages, and which were almost unknown. The result is instructive. Abelard was most famous in his time as a logician and, at every period of his life, he devoted a great part of his energies to this subject. Yet between them, just two manuscripts (Milan, Ambrosiana, M 63 sup.; Paris, BN, lat. 14614: both from the twelfth century) contain the only copies of the greater part of Abelard's logical work; six further manuscripts (all from the twelfth or early thirteenth centuries) complete the total of those which contain logical works by, or possibly by, Abelard. None of his logical writings survives in more than two medieval copies. The Collationes contains some of Abelard's most wide-ranging discussion about good and evil and about religious faith. It is preserved in just three medieval manuscripts, one of them a large fourteenth-century collection of Abelard's work (Oxford, Balliol College, 296). The commentary on St Paul's Letter to the Romans, which includes Abelard's most detailed discussions of topics such as grace, redemption and love, also survives in only three manuscripts, one of which is the Balliol manuscript. Even the most widely copied of Abelard's major works, the Theologia Scholarium, survives in no more than eleven medieval manuscripts.